1.4
* Added item to Issues In Alsa describing a problem on some chipsets which causes blank video unless audio is playing.

1.5
* Reworked codec architecture images to take up less space.
* Added details regarding which chipsets and GPUs use each codec architecture.
* Added basic details of new codec architecture introduced in the GeForce 520.

2
* Added more complete details of new codec architecture introduced in the GeForce 520. This entailed rewriting much of the sections describing ALSA device numbering.
* Changed to single-field numbering scheme.

3
* Updated Incorrect Reporting of Supported Sample Rates to add a link to the fix.

4
* Added item to Issues In Alsa describing a regression which caused ALSA applications to hang when passing through compressed AC3 streams, and the fix for the regression.
* Rewrote dead links to commits on the sound-2.6 project on git.kernel.org to refer to the same commit IDs on the sound project.